Detergent gasoline containing straight-chain tertiary alkyl attached primary amines



United States Patent 3,399,982 r DETERGENT GASOLINE CONTAININGSTRAIGHT-CHAIN TERTIARY ALKYL ATTACHED PRIMARY AMINES George J. Kautsky,El Cerrito, Califi, assignor'to Chevron Research Company, a corporationof Delaware No Drawing. Filed June 8, 1964, Ser. No..373,516 The portionof the term of the patent subsequent to Sept. 19, 1984, has beendisclaimed 3 Claims. (Cl. 44-69) ABSTRACT OF THE DISCLOSURE Leadeddetergent gasoline composition containing straight-chain tertiary alkylattached primary amines and alkyl orthophosphates thereof in which thetertiary alkyl group contains 12 to 30 carbon atoms.

This invention relates to detergent gasolines. More particularly, theinvention is concerned with gasolines containing detergent additiveswhich substantially reduce carburetor deposits in spark ignitioninternal combustion engines.

In the operation of spark ignition internal combustion engines therehave been problems of rough idling and engine stalling, and carburetoradjustments and reconditioning are often necessary to providesatisfactory service. It is found, particularly in the case ofstop-and-go driving in metropolitan areas, that such stalling and idlingproblems are more frequent, especially in the case of multithroatcarburetors of the type employed in many present-day automobiles. It hasbeen determined that the rough idling and engine stalling are primarilydue to the accumulation of deposits in the throttle body section of thecarburetors. As the deposits build up, the amount of air for givenamount of fuel is impeded and greatly reduced, and the air-fuel mixtureis overly rich for satisfactory engine operation. Frequent adjustmentsof the carburetor are needed to overcome the effect of this depositbuildup, and finally it becomes necessary to replace the carburetor orgive it a complete overhaul.

Various additives have been suggested for use in gasoline to cut down onthe buildup of carburetor deposits. However, such additives have usuallysuffered certain disadvantages as to overall effectiveness, and thesearch has continued for more suitable compositions.

It has now been found that deposits in the carburetors of spark ignitioninternal combustion engines are substantially reduced by an improveddetergent gasoline composition comprising a major proportion of ahydrocarbon base fuel boiling in the gasoline boiling range and fromabout 0.0001 to 1.5% by weight of straight-chain tertiary alkyl primaryamine having from about 12 to 30 carbon atoms in the alkyl group.

The straight-chain tertiary alkyl primary amines of the gasolinecompositions of the invention are characterized by the formula in whichone of the branches, R is a straight-chain alkyl group of from 1 to 4carbon atoms and the other branch, R is a straight-chain alkyl group of6 to 28 carbon atoms. Such amines may also be described as aminoalkanes,that is, 2-methyl-2-aminoalkane, 3-methyl-3- aminoalkane or4-methyl-4-aminoalkane in which the alkane is straight-chain andcontains 11 to 29 carbon atoms.

The straight-chain tertiary alkyl primary amines of the gasolinecompositions may also be present in the form of their alkylorthophosphoric acid salts. In such salts, the alkyl groups of theorthophosphoric acid contain from 8 to 18 carbon atoms and arepreferably derived from branched-chain primary alkyl acid esters, alsoknown as acid monoand dialkyl esters of orthophosphoric acid or alkylmonoand dihydrogen phosphates. In these phosphorus compounds, one or twoof the three available acidic hydrogens or orthophosphoric acid havebeen replaced by alkyl groups of 8 to 18 carbon atoms, the remainingacidic hydrogens thus being reactive to form the salts of thestraight-chain tertiary alkyl primary amines.

The alkyl orthophosphoric acids and mixtures of them are convenientlyobtained by reacting an alcohol having the desired alkyl group withphosphorus pentoxide. Ordinarily at least 2 moles of the alcohol will beused for each mole of the phosphorus pentoxide, but preferably fromabout 3 to 4 moles of alcohol per mole of phosphorus pentoxide isemployed. In a particularly suitable mixture, alcohol and phosphoruspentoxide are reacted in a molar ratio of about 3:1 to give monoalkylesters and dialkyl esters in proportions of about 40 to about 60 molepercent of each. Mixtures of alcohols are also desirable. A particularclass of suitable alcohols includes those obtained by the 0x0 processfrom branched-chain olefins, carbon monoxide and hydrogen, thebranchedchain olefins themselves being suitably derived frompolymerization of low molecular weight unsaturated hydrocarbons, such aspropylene and butylene.

The salts of the amines and the alkyl orthophosphoric acids are preparedby reacting the amine and acid using conventional procedures. Oneequivalent of amine is ordinarily reacted With one equivalent of theacid phosphate to produce the substantially neutral salt. Ordinarily,the mole ratio of amine to alkyl orthophosphoric acid will range fromabout 1:0.9 to about 1:04. Illustrative alkyl groups include the octyl,nonyl, decyl, dodecyl, tridecyl, pentadecyl, heptadecyl and octadecylgroups, particularly effective examples of which are the salts of thestraight-chain tertiary alkyl amines and 56.7/43.3 weight percentmixtures of monoand di(tridecyl)orthophosphoric acid.

Although the straight-chain tertiary alkyl primary amine issatisfactorily employed in any amounts sufficient to impart detergencyto the gasoline composition, it is preferred that it be present in thegasoline in amounts from about 0.0001 to 1.5% by weight. For presentpurposes, amounts in the range from about 0.003 to about 0.03% by weightare most satisfactory from the standpoint of effectiveness and cost.

To facilitate handling, it is customary to formulate the improveddetergent additives of this invention as concentrates. Since theadditives are unusually stable and possess good solubilitycharacteristics, these concentrates represent a particular embodiment ofthe invention. In the preparation of the concentrate, the detergentadditive is dissolved in a suitable hydrocarbon or alcohol solventboiling in the range from about to 400 F., preferably an aromatichydrocarbon solvent such as benzene, toluene, xylene, or higher boilingaromatics or aromatic thinners. Aliphatic alcohols of about 3 to 8carbon atoms, such as isopropanol, isobutylcarbinol, n-butanol and thelike, as well as mutually compatible mixtures of such alcohols andhydrocarbon solvents, are also suitable for use with the detergentadditive. The amounts of detergent additive in the concentrate areordinarily at least 10% by weight, and may vary up to about 70% byWeight.

In addition to the detergent additive, other fuel additives may be usedin the gasoline compositions of the invention. The deposit-reducingbenefits are obtained in combination with lead alkyl antiknock agents,such as tetrametyl lead or tetraethyl lead. Such antiknock agents areordinarily employed in amounts sufiicient to enhance the octane number,usually from about 0.5 to 4 ml./ gal.

A nonvolatile light mineral lubricating oil, such as petroleum sprayoil, is also a suitable additive for the gasoline compositions of theinvention. These oils are believed to act as a carrier for disperseddeposits. They are employed in amounts from about 0.05 to 0.5% by volumebased on the final gasoline composition.

The straight-chain tertiary alkyl primary amine detergent additives areavailable from a number of sources. For example, they may be derivedfrom the telomers of ethylene and a secondary alkyl amine, such isisopropyl amine. When prepared in this way, they are mixtures ofhomologous compounds. Such straight-chain tertiary alkyl amines andtheir method of preparation are more fully described in copendingapplication Ser. No. 373,517, filed June 8, 1964, by Donald J. Anderson.Suitable straight-chain tertiary alkyl amines in general are alsoavailable from unsaturated aliphatic hydrocarbons by the so-ealledRitter reaction as set forth in Ritter US. Patent No. 2,573,673, issuedOct. 30, 1951.

The preferred telomer amines have a methyl group as R in the abovestructural formula as already mentioned. Such amines are termed2-methyl-2-aminoalkanes, in which the alkane is a straight-chainpreferably containing 11 to 29 carbon atoms.

Other suitable telomer straight-chain tertiary alkyl primary amines areobtained by reacting a secondary alkyl primary amine having from about 3to about 20 carbon atoms in the alkyl group with an olefin, such asethylene, propylene, isobutylene, etc., ethylene being preferred.Suitable secondary alkyl primary amines are characterized by an alphahydrogen and are generally available in the art, including isopropylamine, Z-aminobutane, 3-aminooctane, 2-aminopentadecane, mixtures of 2-,3- and 4-aminoalkanes containing from to carbon atoms as obtained byamination of thermally cracked wax olefin mixtures and the like, as wellas secondary cycloalkyl primary amines, such as cyclohexyl amine. Thestraight-chain tertiary alkyl primary amines derived from thesesecondary alkyl primary amines have the general formula in which R is asdescribed above, and R and R are alkyl groups or cycloalkyl groupscharacteristic of the aforementioned secondary amines.

The improved gasoline compositions containing the straight-chaintertiary alkyl primary amines in accordance with the invention provideexcellent detergent performance compared to gasoline compositionscontaining other alkyl amines. Such detergent properties are determinedby the generally accepted method of appraising the gasoline compositionsin the glass throttle body engine test, which has been especiallydeveloped to observe and to evaluate deposits in the carburetors oftypical gasoline induction systems.

In the Glass Throttle Body Test, a 6-cylinder Plymouth automobile engineis set up in the laboratory and is provided with a conventionalcarburetor by the introduction of a removable glass throttle bodysection between the carburetor body and the original cast iron throttlebody. This glass throttle body is a section of glass tubing 4" thick, ofapproximately 1%" outside diameter and about 1% long. An automaticcycler or timer, which consists of a constant-speed electric motor and amagnetic clutch, is provided for insuring cyclic operation of the enginewith 7.5 min. idle periods followed by five accelerations to 2000 r.p.m.Crankcase fumes are vented to the carburetor air inlet, since thesefumes are now known to be responsible for the larger portion of thedeposits. The engine is started up, using leaded gasoline containing aconventional amount of tetraethyl lead (1.5 ml./gal.), but nosurface-active additives of any kind. It is run for 4 hours with theblowby fumes being drawn in at the air intake. The engine is thenstopped, the glass body is removed, and both sides of its arephotographed. Thereupon the dirty glass body is again installed on theengine and run for one hour on the same leaded base gasoline compoundedwith the detergent-action additive. This time the blowby fumes are notpiped to the carburetor. After the run is completed, the glass throttlebody is again photographed, and the effectiveness of thedetergent-containing gasoline (the percentage of cleanup of denosits) isvisuallv estimated In these tests, representative straight-chaintertiary alkyl primary amines, namely, the 2-methyl-2-aminoalkanes asdescribed above, were evaluated in the gasoline composition at aconcentration of 0.003% by weight. The results are given in thefollowing table.

TABLE Cleanup, Amine, average composition: percent (A)Z-methyl-2-aminohexadecane 74 (B) 2-methyl-2-aminononadecane 62 (C)2-methyl-2 aminooctaeicosane 67 Substance A is the telomer of ethyleneand isopropyl amine containing an average of 17 carbon atoms. It has amolecular weight of 244 and boils from to C. at 2 mm. Hg pressure.

Substance B is the telomer of ethylene and isopropyl amine containing anaverage of 20 carbon atoms. It has a molecular weight of 301 and boilsfrom 150 to C. at 2 mm. Hg pressure.

Substance C is the telomer of ethylene and isopropyl amine containing anaverage of 29 carbon atoms. It has a molecular Weight of 406 and boilsfrom to 295 C. at 1 mm. Hg pressure.

From the above tests, it will be noted that the 2-methyl- 2-aminoalkanesgive excellent carburetor throttle body cleanups of as high as 74%. Bycomparison, a commercial detergent-action aminoalkylene amide preparedfrom oleic acid and hydroxyethyl ethylenediamine at the sameconcentration gave 55% cleanup.

While the character of this invention has been described in detail withnumerous examples, this has been done by way of illustration only andwithout limitation of the invention. It will be apparent to thoseskilled in the art that numerous modifications and variations of theillustrative examples may be made in the practice of the inventionwithin the scope of the following claims.

I claim:

1. An improved detergent gasoline composition comprising a majorproportion of a hydrocarbon base fuel boiling in the gasoline boilingrange, lead alkyl antiknock agent in amount sufficient to enhance theoctane number and from about 0.0001 to 1.5 percent by weight of astraight-chain tertiary alkyl attached primary amine having from about12 to 30 carbon atoms in the alkyl group of the formula:

in which one of the branches, R is methyl and the other branch, R is astraight-chain n-alkyl group of 6 to 28 carbon atoms.

2. The composition of claim 1 in which the amine is derived bytelomerization of ethylene and isopropyl amine and contains 15 to 20carbon atoms per molecule.

3. An improved detergent gasoline concentrate consisting essentially ofa hydrocarbon solvent and from 10 to 75 percent by weight of thestraight-chain tertiary alkyl primary amine of the gasoline compositionof claim 1.

References Cited UNITED STATES PATENTS 7/ 1943 Sweeney 4472 7/ 1960Andress 44-72 1/1931 Lovell et al. 4472 4/ 1934 Magness 44-80 10 62,684,292 7/1954 Caron et al. 4463 2,706,677 4/1955 Duncan et al. 44-632,840,461 6/1958 Duncan et al. 4472 FOREIGN PATENTS 796,427 6/1958 GreatBritain.

DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner.

